Reciprocating piston pump operating on pressure medium

ABSTRACT

The present invention relates to a reciprocating piston pump comprising: at least one cylinder with an inlet for a pressure medium; a piston slidable in the cylinder between a first and a second position, and forming a pressure chamber in the cylinder; a first valve member which is received in the piston and which in an open position mutually connects the cylinder spaces on either side of the piston; a second valve member which is received in the piston and which in an open position connects a pressure medium passage formed in the piston to an outlet of the pump; a resilient member urging the piston in the first position; an actuating member connected to the valve members and which are embodied such that in the first position the first valve member is closed and the second valve member is opened and in the second position the first valve member is opened and the second valve member is closed, wherein the piston is moved to the second position by the pressure medium.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 to application serial number 07075373.6 filed in the European Patent Office on May 15, 2007 entitled “RECIPROCATING PISTON PUMP OPERATING ON PRESSURE MEDIUM,” which is incorporated by reference into the instant application as if set forth verbatim.

FIELD OF THE INVENTION

The present invention relates generally to pumps, and more particularly to reciprocating piston pumps operated with a pressure medium.

BACKGROUND OF THE INVENTION

Existing reciprocating piston pumps are used to transport a medium from a pump inlet connected to a tank to a pump outlet opening. These pumps are driven by a motor that slidably moves a piston of the pump in the cylinder, thereby forming a pressure chamber in the cylinder. By opening and closing valves at the appropriate times, the pressurized fluid is propelled out of the pump. However, existing pumps require separate motors and connecting means, thereby increasing the number of parts, maintenance etc.

Accordingly there is a need for a reciprocating piston pump which is more efficient and does not require separate drive means.

SUMMARY OF THE INVENTION

This objective is achieved with the reciprocating piston pump of the present invention.

The piston of the pump will slide in the cylinder from a first to a second position by supplying the pump inlet with a pressure medium. Valve members are received or incorporated in the piston itself and are actuated by the actuating members. By opening and closing the valve members at the appropriate times, the pressure medium that is brought into the cylinder during the movement of the piston from a first position to a second position will be transferred to the other side of the piston during the piston's return from the second position to the first position. In one embodiment, during the return stroke to the first position, the first valve member is open and mutually connects the cylinder spaces on either side of the piston. During the movement of the piston from the first position to the second position, the pressure medium, which has been transferred from the pump inlet to the pressure chamber, is transported out of the pump via the pump outlet. During this piston stroke the second valve member is in an open position connecting the pressure chamber to the outlet. A pressure medium moves the piston from the first position to the second position in the cylinder, and a resilient member will urge the piston from the second position to the first position. The interplay of the resilient member and piston enables the piston pump to operate without requiring a separate motor for driving the pump. This results in a more efficient pumping and does not require separate drive means.

A preferred embodiment of the piston pump according to the present invention comprises a first plunger for uptake of a first medium from a second inlet to a second chamber.

The plunger moves from a first to a second position thereby creating an under-pressure that will cause uptake of a first medium through a second inlet of the pump. This enables transport of the first medium from a tank (or the like) to an outlet. Preferably, the pump comprises sealing means for sealing the second chamber against a return flow of medium. Advantageously, the pump comprises a connecting member connecting the first plunger with the piston to simultaneously move the plunger and piston. Through this simultaneous movement of the plunger and piston, both the pressure medium and the first medium are transported to the pump outlet. In other words, the movement of the piston, either by the pressure medium or the resilient means, causes uptake and transport of the first medium to the pump outlet. Preferably, the pump outlet for the first medium and the pressure medium is the same. Therefore, a mixture of the pressure medium with the first medium is provided. For example, in the case of the pressure medium being water and the first medium being a soap concentrate, such a mixture would result in a liquid soap ready for use.

In a further preferred embodiment according to the present invention the pump further comprises a second plunger for uptake of a second medium from a third inlet to a third chamber.

By moving the second plunger from a first position to a second position an under-pressure will be created in the third chamber. This will cause uptake of a second medium from a third inlet. This will enable transport of this second medium from a tank (or the like) to an outlet. Preferably, the pump comprises second sealing means for sealing the third chamber against a return flow of medium. Further, the second pump preferably comprises a second connecting member connecting the second plunger to the piston (and preferably also to the first plunger) to simultaneously move the piston and second plunger (and preferably the first plunger) for transport of the pressure medium, and second medium (and preferably also the first medium) to the pump outlet. In a preferred embodiment, the pump outlet for the pressure medium, the first medium, and the second medium are the same. This results in a mixture of these media in the outlet flow. For example, in the case of the pressure medium being water and the first and second media being soap concentrates, the outflow of the pump will be a liquid soap ready for use. Preferably, the third inlet is at a different position as the second inlet to enable uptake of two different media, or the same medium at different altitudes in a tank with different densities. In case of the third inlet taking media from the same tank it is possible to have a mixture at the pump outlet of the pressure medium and two different densities of the other medium thereby creating a consistent mixture.

In a further preferred embodiment according to the present invention the pump a comprises float member for connecting the third inlet to the second chamber.

By the use of the float member it is possible to keep the third inlet at the upper level of, for example, a storage tank with decreasing level as the pumping operation continues. With the float member keeping the third inlet at a different level as compared to the second inlet during the pumping operation density differences in a storage tank are compensated. Preferably, the float member comprises a pivoting member to ensure the third pump inlet remains above the second inlet. Also preferably, the float member comprises a lock for locking and unlocking the pivoting member. This enables the float member to float on the top surface of the fluid in, for example, a storage tank. Therefore, the third inlet can be positioned just below this top level. As fluid is removed by the pumping operation, and the level in the tank thus decreases, the float member will pivot around the pivoting member to remain floating on the medium and thereby keeping the third inlet just below this top level. By providing a lock it is possible to put the piston pump into a storage tank after which the lock is disabled and the float member unlocked. The piston pump may then start operation. In case the piston pump needs to be removed from the storage tank the float member may be retracted to its original position by enabling the lock. This may be relevant, for example, when a storage tank is not fully empty and the pump needs to be removed.

In a further preferred embodiment according to the present invention the pump further comprises at least one shock absorber with a plunger.

When the piston moves from the first position to the second position, and medium is transported from the pressure chamber to the pump outlet, part of the outgoing medium is temporarily stored by the absorber. This stored volume is output during the return movement of the piston from the second position to the first position due to the compressed air volume on the other side of the plunger. This smoothens the pump output.

In a further preferred embodiment according to the present invention the pump further comprises disposing means for disposing an amount of an agent medium in at least one chamber.

The disposing means will provide a certain amount of one or more agents into one of the chambers of the piston pump during a stroke of the piston and/or plungers. Such agent may include a colouring agent supplying a specific colour to the inlet space of the pressure medium, thereby colouring the outflow from the piston pump. This will be relevant e.g. in case the outflow of the piston pump has the same colour as the incoming flow. E.g. in case of the pressure medium being water and the first and/or second medium being a soap concentrate a colouring agent will enable to distinguish the ingoing water from the outgoing soap. Also other agents may be used to provide specific characteristics to the outflow of the piston pump. Preferably, the pump comprises connecting means for connecting the tank of agents medium to the pump. This enables the provision of a single piece of equipment for both the pump and the agent disposal means. Furthermore, by directly coupling the agent medium to the pump it is possible to use the movement of the piston for disposal of the agent in the main pressure chamber related to this piston.

In a further preferred embodiment according to the present invention the pressure medium is a fluid.

A fluid, like water, used for the pressure medium would allow for movement of the piston in the cylinder. Furthermore, as the piston is moved due to the resilient means, the fluid is transported to the pump outlet and preferably mixed with one or two other media like, for example, soap concentrate. Such soap concentrate may constitute of a mix of various chemicals with a rather large variation of molecular weight. This concentrate may be taken from a storage tank. Typically, after a relatively short period of time, such as about 5 minutes, it is possible to distinguish an upper part of, for example, 60% low density concentrate and a lower part of, for example, 40% higher density concentrate. To achieve a consistent outflow of soap at the pump outlet such a mixture must reflect the differences in density of the soap concentrate. In the example mentioned here, 60% of the soap concentrate has to be taken from the upper part by the third inlet of the pump and the remaining 40% of the lower part by the second inlet of the pump. Depending on the desired characteristics of the soap product, the ratio of soap to water will vary. Different ratios may be achieved by changing the dimensions of the pump parts. For example, different uptakes of volume from the storage tank by the second and/or third inlet will be possible. By choosing the second and third chambers of the desired dimensions it is possible to have an outflow with every desired concentrations of media. Although in the preferred embodiment the ratio of the first pressure chamber and second chamber is about 1:11, also ratios 1:10 and 1:12 are possible. However, it will be understood that far different ratios will be possible, such as anywhere between 1:1 and 1:100, depending on the density differences in the relevant media. This will include the ratios 1:23 and 1:35 that are also relevant for soap concentrates.

The volumes of the chambers used by the first and second plunger have to be chosen according to the characteristics of the soap concentrate. In the example mentioned here, this ratio would be 2:3, although ratios between 1:2 and 2:1 would also be possible. However, it will be understood that ratios anywhere from 1:100 to 100:1 would also be possible.

The invention further relates to a method for pumping at least one medium using the reciprocating piston pump according to the invention. Using this method the advantages mentioned before will be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a reciprocating piston pump according to the invention put into a storage tank;

FIG. 2 shows the piston pump of FIG. 1 extracted from the storage tank;

FIGS. 3A and B show the piston pump of FIG. 1 with the lock engaged and disengaged respectively;

FIG. 4 shows the piston pump of FIG. 1 with the float member rotating;

FIGS. 5A and B show the piston pump of FIG. 1;

FIG. 6 shows the valve members in the piston of the pump of FIG. 5;

FIG. 7 shows the shock absorber in the piston of the pump of FIG. 5;

FIG. 8 shows the mixing chamber for the two soap concentrates;

FIG. 9 shows the second chamber;

FIG. 10 shows the pivot axis of the floating means;

FIG. 11 shows the second pump inlet;

FIG. 12 shows the third chamber; and

FIG. 13 shows an alternative configuration for the agent supply.

DETAILED DESCRIPTION

Exemplary embodiments of the invention are described in detail below with reference to the appended figures, wherein like elements are reference with like numerals throughout. The figures are not necessarily drawn to scale and do not necessarily show every detail or structure of the various embodiments of the invention, but rather illustrate exemplary embodiments and mechanical features in order to provide and enabling description of such embodiments.

A reciprocating piston pump is located in a storage tank 4 that is put on a pallet 6 (FIG. 1). The piston pump 2 has an inlet 8 for supply of water as a pressure medium and an outlet 10 for the outgoing flow. The pump 2 comprises a second inlet or inlets 12 and a third inlet or inlets 14 for uptake of a relatively low density fluid 16 and a relatively high density fluid 18, respectively. The pump 2 is connected to tank 4 with connector 20. The pump 2 is put at the bottom of the tank 4 with inlet 14. As the volume of the fluid in tank 4 is relatively high the float member 22 will be in an approximately horizontal position after it pivots around pivot axis 24. To enable extraction of pump 2 from the tank 4 the float member 22 is locked against the pump (FIG. 2). Also in case the pump 2 is entered into the tank 4 the lock is engaged and will only be disengaged after pump 2 has reached its position inside tank 4 (FIGS. 3A and 3B). After disengaging the lock the float member 22 will rotate around pivot axis 24, provided there is sufficient level of fluid in tank 4 (FIG. 4) to buoy the float member. The float member 22 pivots in the direction indicated by arrow A.

Pump 2 (FIGS. 5A and 5B) comprises a housing 26 wherein a main piston 28 slides. The piston 28 is connected to a central rod 30. The pressure medium, in this case water, enters the pump 2 at the inlet body 32. As soon as the pressure medium is allowed to enter the pump 2, it will cause the piston 28 to move downwards. Due to this downward movement the pressure chamber 34 will become smaller thereby increasing the pressure inside it. To relieve this increased pressure, the fluid in chamber 34 can escape through valve member 38 (when open) and leave the pump 2 at the pump outlet 36.

Valve member 38 (FIG. 6) comprises an upper valve part 40 and a lower valve part 42. The valve members 40 and 42 are received slidably in the piston 28. The protruding ends of the valve bodies form actuators which interact respectively with stops formed inside the chamber 34 by the fluid head disk 44 and with a stop at the opposite end of the cylinder formed by the inlet body 32. In the position shown in FIGS. 5 and 6, the pressure medium flows via the inlet body 32 towards the piston 28. The pressure medium pushes the piston 28 downwards counter to the force of a spring. The fluid in chamber 34 flows through the opening between the lower valve part 42 and the piston channel through the pump outlet 36. As the actuator or valve spring 46 meets its stop at the end of the downward movements, the valve member 38 will move relative to the piston 28 and the connection between outlet 36 and room 34 will be closed. At the same time the upper valve part 40 will be opened and both rooms opposite of the piston 28 will be connected. As the spring urges the piston 28 back to this beginning position, as shown in FIGS. 5 and 6, the fluid will be transported from above the piston 28 to the chamber 34 below the piston 28. At the end of this return stroke when the piston 28 returns to the beginning position the valve spring 46 will move the valve member 38 relative to the piston 28 so that the next cycles may start.

Piston 28 comprises three shock absorbers 48 (FIG. 7). The shock absorber 48 contains a shock absorber cap 50, a shock absorber barrel 52 and a shock absorber piston 54. This will compensate for undesired pressure variations and results in a more constant outflow. Fluid enters the space between absorber piston 54 and the bottom of barrel 52. The fluid urges the piston 54 upward by allowing fluid to enter the absorber 48 through opening 55, thereby increasing the air pressure in the space above piston 54. Fluid is collected in the space below piston 54 during the movement of the main piston 28 from its upper to its lower position. In the return movement the air pressure above piston 54 pushes piston 54 downward thereby transporting the fluid to the outlet. Piston 54 is cup-shaped to increase the volume of the shock absorber 48.

The central rod 30 is connected to a two staged plunger. The large upper plunger 56 is connected to the piston 28 with an area constituting a ratio between the pressure medium and the second (and further) medium of about 11:1. In the embodiment shown in the figures the lower and smaller plunger section has a surface area of 60% of the upper plunger leaving a ring shaped area of 40%. In the shown embodiment 60% of the second and further medium is taken from the upper part of the storage tank volume, while the remaining 40% are taken from the bottom of this storage tank. The piston rod 30 is connected with the piston 28 and the plungers 56 and 58. A downward movement of piston 28 results in a simultaneous downward movement of the upper plunger 56 and lower plunger 58. The chamber 60 between the lower plunger 58 and the fluid at fluid head 62 is emptied due to the downward movement of the upper plunger 56. The chamber 64 is also emptied in this same downward movement of the piston 28.

The upper outlet valve 66 (FIG. 8) is open during the downward movement of the piston 28 thereby allowing the medium in chamber 60 to be transported towards piston 28 and the pump outlet 36. An upper support ring 68 lies against fluid head disk 44 and comprises upper support ring inner seal 70, an upper outlet outer seal 72 and also an upper support ring inner seal 74. The outlet valve 66 is urged back from its second position to its first position due to the upper outlet spring 76.

The lower plunger 58 (FIG. 9) in its downward movement moves the lower outlet valve 78 and allows transport of the medium in chamber 64 towards piston 28 and pump outlet 36. The lower outlet spring 80 closes valve 78 when returning from its second position to its first position.

The central rod 30 comprises a lower seal 82. The fluid head extension 84 is connected to a lower support ring 86. The support ring 86 contains inner seals 88 and lower seals 90. The fluid head extension 84 contains an upper seal 92 and lower seal 94. The valve 78 contains an outer seal 96.

The chamber 64 is supplied with medium through suction pipe 98 in the piston movement from the second position back to its first position. The medium is supplied through suction pipe 98 towards room 64 and an assembly 98 prevents a return flow of medium back into suction pipe 98. Assembly 100 (FIG. 9) comprises a lower inlet insert 102, a lower inlet body 104, a lower inlet gland 106 and a lower inlet poppet 108. Furthermore, the assembly 100 is provided with a lower inlet body outer seal 110, a lower inlet poppet seal 112 and two lower inlet body inlet seals 114.

The suction pipe 98 is connected to a pivotable inlet through coupling assembly 116 (FIG. 10). The assembly 116 pivots around a pivot axis created by balance pivot bolt 118. The assembly 116 further comprises two balance connectors 120, two balance pivot bearings 122 and the balance pivot 124. The assembly 116 is sealed using four balance intake extension seals 126, two balance pivot seals 128 and two balance connector seals 130. The assembly 116 is connected to its inlet through a balance open union 132 and a balance float bolt 134 leading to the inlet located in the balance float 136. The inlet of floating part 136 (FIG. 5A) has a counter weight 138 that is connected by a horse shoe connection 140 with the counter weight extension 142. These parts are connected with four balance connectors closed unions 144.

Room 60 is supplied with medium through flexible suction pipe 146 that is connected to the corresponding inlet assembly 148 (FIG. 11). The assembly 148 comprises a bottom disk 150 and a bottom disk insert 152. The assembly 148 further comprises a bottom disk retaining ring 154.

The suction pipe 146 supplies the medium at the other side through an upper inlet assembly 156 (FIG. 12). Each of the two suction pipes 146 inputs the medium through a separate upper inlet assembly 156. Each assembly 156 comprises an upper inlet poppet 158, a lower supporting ring outer seal 160 and an upper inlet spring 162.

To enable intake of medium from the top level of a liquid in a storage tank the float member 22 is allowed to pivot around pivot axis 24, as described before. To enable removal of the pump 2 from the storage tank it is required that the floating device returns to its original position. This is achieved by a locking assembly comprising a lock spring 164, a mounting gland 166, a lock sleeve 168, a lock body 170, a large balance protector 172 and a small balance protector 174 (see FIG. 5). The assembly further comprises a lock body support 176. The balance protector 174 is connected to the pivoting assembly 156 through a rod 178, washer 180 and nut 182 with bolt 184. The large protector 172 is connected through the threaded rod 186, washer 188 and nut 190. The protectors 172, 174 are connected to the pump 2 (FIG. 5B) and do not pivot with the float member 22. The lock body 170 comprises a cam 171 that engages the float member 22. By movement of the lock body 170 and cam 171, the float member 22 is locked or unlocked for its pivotal movement. When unlocked the float member 22 starts to pivot, depending on the level of fluid in the tank 4, and engages the lock body 170 when reaching a horizontal level.

To urge the piston 28 from its second position to its first position, spring 204 engages spring support 206 with spring bushing 208, as shown in FIG. 5. On its other end spring 204 lies against spring support 210 that is connected to inlet body 32. The rod 200 consists of a bottom part 212 and an upper part 214 that are connected through a union 216 comprising a seal 218. Inlet body 32 is sealed with an inlet body seal 220. The spring support 210 is sealed with seals 222, 224 and backup seal 226.

In the pump 2, agent medium is supplied from agent supply chamber 192. As shown in FIG. 13, the agent medium is supplied using a separate plunger 228. The diameter extension 230 at the end of the rod, changing from 44 to 46 mm, drives the plunger 228. Thereby the movements of this plunger 228 are connected with piston 28. In this embodiment the displacement of the plunger 228 would be 1 mm with a diameter of 10 mm resulting in a volumetric displacement of about 79 mm³. The inlet and outlet valves for the plunger comprise steel balls 232 and 234 in a bore of about 3.2 mm with a stroke of about 0.4 mm. The balls seal in one direction. A rubber spring 236 pushes the large ball 238 and the plunger 228 against the rod. The rod extension compresses the spring 236. As a result the spring 236 increases its diameter filling the space inside the plunger and insert 240 preventing a substantial dead volume. This configuration will, in relevant cases, ensure a more constant supply of agent medium and enable a smooth start-up of the agent supply.

In an alternative configuration, agent medium is supplied from an agent supply room 192, shown in FIG. 5. This room 192 comprises an agent filler cap 194 for refilling and a top lid. The room 192 is sealed with a filler cap seal 198, through which the top rod 200 may be moved. This rod is supplied with a top cap 202. In the end of the stroke of the piston 28 moving from the first position to the second position a few droplets of the agents medium are pushed out of the agent supply room 192 into the room above the piston 28. This is accomplished by an agent pusher that at the end of the stroke, enters into a cone of spring support 210 thereby pushing the desired droplets of agents medium by the seal into the room above the piston 28 during the movement from first position to the second position.

As an example of an alternative embodiment, the pressure medium may be water and the first and second medium may be a soap concentrate. Other media will also be possible. In addition, it will be possible to supply all inlets with different media from different storage tanks. Also, it would be possible to have a supply of agent medium already in the pressure medium instead of a separate supply room. The configuration of the pump may be changed, for example in that room 60 is connected to the inlet of the float member instead of the bottom inlet.

Various modifications and alterations of the invention will become apparent to those skilled in the art without departing from the spirit and scope of the invention, which is defined by the accompanying claims. For example, it should be noted that steps recited in any method claims below do not necessarily need to be performed in the order they are recited. For example, in certain embodiments, steps may be performed simultaneously. The accompanying claims should be constructed with these principles in mind.

Any element in a claim that does not explicitly state “means for” performing a specified function or “step for” performing a specified function is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. § 112, ¶16. 

1. A reciprocating piston pump comprising: a. at least one cylinder with an inlet for a pressure medium; b. a piston slidable in the cylinder between a first and a second position, and forming a pressure chamber in the cylinder; c. a first valve member which is received in the piston and which in an open position mutually connects the cylinder spaces on either side of the piston; d. a second valve member which is received in the piston and which in an open position connects a pressure medium passage formed in the piston to an outlet of the pump; e. a resilient member urging the piston in the first position; f. actuating means which are connected to the valve members and which are embodied such that in the first position the first valve member is closed and the second valve member is opened and in the second position the first valve member is opened and the second valve member is closed, wherein the piston is moved to the second position by the pressure medium.
 2. Reciprocating piston pump according to claim 1, wherein the pressure medium fed at the pump inlet, in one stroke of the piston, moves the piston from a first position to a second position, wherein in said stroke the pressure medium in the pressure chamber is transported to the pump outlet.
 3. Reciprocating piston pump according to claim 2, wherein the pump comprising a first plunger for uptake of a first medium from a second inlet to a second chamber.
 4. Reciprocating piston pump according to claim 3, wherein the pump further comprises: a. a first sealing means for sealing the second chamber against a return flow of medium; and b. a first connecting means for connecting the first plunger to the piston to simultaneously move the plunger and piston for transporting both the pressure medium and the first medium to the pump outlet.
 5. Reciprocating piston pump according to claim 3 or 4, wherein the pump comprising a second plunger for uptake of a second medium from a third inlet to a third chamber.
 6. Reciprocating piston pump according to claim 5, wherein the pump further comprises: a. second sealing means for sealing the third chamber against a return flow of medium; and b. second connecting means for connecting the second plunger to the piston and to the first plunger to simultaneously move the piston, first and second plunger for transport of the pressure medium and first and second medium to the pump outlet.
 7. Reciprocating piston pump according to claim 5 or 6, wherein the pump comprises floating means for connecting the third inlet to the second chamber.
 8. Reciprocating piston pump according to claim 7, wherein the floating means comprising: a. pivoting means to keep the second pump inlet above the first inlet in the second medium; and b. locking means for locking and unlocking the pivoting means. c.
 9. A reciprocating piston pump according to claim 1, wherein the pump further comprises at least one shock absorber located in the piston with a plunger for smoothing the outflow of the pump.
 10. Reciprocating piston pump according to claim 1, wherein the pump further comprises disposing means for disposing an amount of an agent medium in at least one chamber.
 11. Reciprocating piston pump according to claim 10, wherein the pump comprising agent connecting means for connecting the volume of agent medium to the pump.
 12. Reciprocating piston pump according to claim 1 wherein the pressure medium is a fluid.
 13. Reciprocating piston pump according to claim 3 or 4, wherein the ratio of the volume of the first and second chambers, or second and third chambers, is between 10 and
 12. 14. Reciprocating piston pump according to claim 5 or 6, wherein the ratios between the volume of the second and third pressure chambers is between 0.5 and 2.0.
 15. A Method for pumping at least one medium using a reciprocating piston pump, the method comprising: a. using a pressure medium to drive a piston in a cylinder, wherein movement of the piston varies the pressure inside a pressure chamber; b. intaking a first medium through a first inlet by decreasing the pressure inside the pressure chamber, and c. exhausting through a first outlet a mixture of the pressure medium and the first medium by increasing the pressure inside the pressure chamber.
 16. The method of claim 15 further comprising: a. intaking a second medium through a second inlet by decreasing the pressure inside the pressure chamber, and b. exhausting through the first outlet a mixture of the pressure medium, the first medium, and the second medium by increasing the pressure inside the pressure chamber.
 17. The method of claim 15 wherein the pump is inserted into a tank containing the first medium and a lock member locks a float member to a pump body, wherein the first inlet is located on the float member, the method further comprising: a. Unlocking the lock member to release the float member, b. The float member buoying upwards and pivoting to the upper surface of the first medium inside the tank, and c. Intaking the first medium through the first inlet at the upper surface of the first medium inside the tank.
 18. The method of claim 16 wherein the pump is inserted into a tank containing the first medium and the second medium, the first medium being less dense than the second medium, and wherein a lock member locks a float member to a pump body, wherein the first inlet is located on the float member and the second inlet is located on the pump body, the method further comprising: a. unlocking the lock member to release the float member, b. the float member buoying upwards and pivoting to the upper surface of the first medium inside the tank, c. intaking the first medium through the first inlet at the upper surface of the first medium inside the tank, and d. intaking the second medium through the second inlet below the interface between the first medium and the second medium inside the tank. 